1. Field of the Invention
The present invention relates to a device for aligning and retaining two rails having abutting ends to be welded together, the rails comprising a rail head having a tread, an underside and sides connecting the tread and underside, a rail foot and a web connecting the rail head and foot, which comprises a rigid frame, abutments for the rail head on the frame spaced from each in a longitudinal direction along the rails, and retaining yokes for frictionally engaging the rails and clamping the device to the rails, the retaining yokes being associated with the frame and extending in a direction extending perpendicular to the longitudinal direction.
2. Description of the Prior Art
European patent No. 17,520 discloses such a device for centering abutting ends of two rails. It comprises a frame extending in a horizontal plane and positioned sideways of the rail heads, and abutments for engaging the rail head tread and one of the rail head sides on the frame. Additional abutments for the opposite rail head sides formed as threaded spindles extending horizontally and perpendicularly to the longitudinal direction of the rails are adjustably mounted on a retaining yoke connected to the frame. With this device, it is not possible to align the rail head treads of the rail ends to be welded together in a single plane, particularly if the cross sectional profiles differ from each other.
German patent No. 2,830,006 discloses a structurally very complex device for aligning and retaining abutting rail ends. The rail ends are centered by jaws hydraulically pressed against the rail webs. Again, the rail head treads cannot be accurately aligned in a common plane.
U.S. Pat. No. 5,136,140 discloses a rail tensioning apparatus with which the abutting rail ends may be pulled together under very high tensile forces while being centered in respect of each other. This apparatus serves primarily to correct any minor bending caused by the high tensile forces.